Idrive, welcome to the forum. Your question is not as straight forward as you might think. 59 F100's didn't offer a 3.25 differential and if your truck is riding on different sized tires from stock, then you will need to consider that also.
Good luck in your quest.

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For Ford the third time was the charm
Third generation Ford truck 57-60
1959 F250 4x4
Wally

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